X10 Community Forum
📸Cameras & Camera Software => Camera General Discussion => Topic started by: john to perdo on August 05, 2005, 01:43:29 PM
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Hi:Has anyone found an easy way to soup up
a CM19a USB transceiver for better range?
(like extend the antenna to the length of
other 315MHz devices, or add a ground plane
under the unit). These are both
possibilities, but I thought I would ask if
anyone has tried this before I dug into it.
As it stands it almost makes it to the
location I desire. I don't need much of an
improvement.
Thanks, John
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Hi John;
I currently have a spare CM19A in stock
that I can afford to "Play" with (the case
was damaged in a clumsy, big footed helper
incident)and have been wondering the same
question myself, Maybe I can answer this
question for both of us. How long would you
recommend extending the antenna?
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Hi: Sorry for the delayed response, I would
start at about a total length of about 12 or
13 inches. I think that is pretty close to
one quarter wave length at 315 MHz. One
could also put a metal cookie sheet under
the CM19a, that also might help. You might
have to ground the cookie sheet to something
(like a cable shield) on the inside of the
unit to get full advantage of the cookie
sheet. I would start with a longer antenna
and then start messing with the cookie sheet.
THanks, John
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What is the CM19A used for exactly? I have
one and really do not know what it used for.
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It is an X-10 RF(315MHz) to USB interface.
It is used to transmit signals (via rf) to
or from your computer to things like the
Ninja pan and tilt camera mount. It is a bi-
directional unit and can also receive
signals from the various X-10 hand held
units and rf motion sensors etc and send
them into your computer. It only is useful
IF you have software on your computer that
interfaces with X10 devices. I use it to
couple my Home Seer (www.homwseer.com)
software package to my Ninja camera mounts.
Home Seer tells the camera mounts which
direction to turn. Hope this helps.
John
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FCC site says it is 312Mhz. So the antenna
maybe slightly shorter than for a 315Mhz. I
have seen web pages on other uses for that
module. Will post data if I find it.
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Thanks, Yep, Actually I got the 12 or 13
inches mentioned previously by measuring an
antenna on an X10 AC device. I just did a
rough calculation to see if the 12 to 13
inches approximated a quarter wave antenna
at 315 MHz and it seemed OK. I didn't check
part 15 of the fcc regs but you are correct,
if part 15 says the band is 312 HHz. then
that is what we should be using. Apparently
people commonly round it off and call it 315.
Thanks again, John
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I used the FCC registration number. Most of
all the X10 stuff is 310Mhz. The CM19A was
listed as 312Mhz.
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So did you try this and did it work? I would
like to increase the range on mine as well..
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Yep, I extended the total antenna length to
13 inches and it seems to have made the
difference. It now works every time (so
far). I think it was on the hairy edge of
working before, and this seems to have made
the difference. It now works consistently.
For what its worth, I set the CM19a on a
wooden shelf and hung the 13 inch antenna
straight down off the shelf and I ran the
USB cable to the CM19a in along the shelf
perpendicular to the antenna. There is no
other metal near the CM19a. Hope this helps.
John
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So how did you extend the antenna? What did
you use?
Thanks!
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I just used one conductor from a piece of
telephone wire, the yellow one to be exact.
It is just a piece of a number 24 or 26
solid wire. Nothing special.
John
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And did you just solder / splice it into the
wire already there or did you totally remove
the one and add this one?
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I used the existing wire. I just nipped off
about 1/4 inch of insulation from the
antenna and twisted the phone wire to it
(after nipping off 1/4 of insulation from
the phone wire). It isn't really necessary
to solder a connection like this (unless you
really want to). John
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And that helped improve the range? Does it
have to be an exact length?
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It didn't work before the additional length
was added. It does work now. That's all I
know.
Typically the length tolerances on antennas
of this sort can be + or - 5% without much
effect. If you are within 1/2 inch you will
probably be OK. I haven't run any tests and
will now leave it alone since it works.
John
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It didn't work before the additional length
was added. It does work now. That's all I
know.
Typically the length tolerances on antennas
of this sort can be + or - 5% without much
effect. If you are within 1/2 inch you will
probably be OK. I haven't run any tests and
will now leave it alone since it works.
John
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IT WORKS ! (Thanks, John)
I soldered a short length of telephone wire
to a CM-19A antenna for a total antenna
length of 13". The CM-19A's signal now
reaches my two Vanguard cameras with
significant strength such that the critical
camera switching and PTZ functions now work
(they didn't work before). Would still like
to move the cameras farther away from the CM-
19A, so I'm looking for a way to
electronically amplify the CM-19A's signal.
Purchased and tried X-10's signal repeater
(an X-10 tech's solution when I called), but
it does not respond to the CM-19A signal.
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I TO HAVE HAD MANY PROBLEMS WITH CM19A. I
TRIED DIFERENT LOCATIONS AND WIRE
EXTENTIONS FOR THE ANTENNA. BUT JUST A FEW
DAYS AGO I BOUGHT A SCANNER ANTENNA FROM
RADIO SHACK IT WAS LISTED AS 30 TO 512 MHZ.
IT SEEMS TO HELP THE DISTANCE PROUBLEM. BUT
I TO WOULD LIKE TO AMPLIFY THIS UNIT.
Indoor Scanner Antenna
Model: 20-161
Catalog #: 20-161
30 to 512MHz. Extends to 40".
$12.99
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Michael: I believe amplifing the CM-19a
might be a bit of a problem. If I remember
correctly the CM19a is both a transmitter
and receiver. This means that any amplifier
should work in both directions, and that is
a really tough requirement for any engineer
(especially one who does not have access to
the design information for the CM19a.)
If it were absolutely necessary to make an
amplifier, you probably would want to use
the CM19a only as a transmitter and amplify
its output signal only, and then use some
other X10 receiver to do the receiving for
the system. Using the CM19a as an exciter
for a more powerful transmitter could be
done. There may even be X10 boosters that
might work, but they would be a gamble
(unless someone has done this before.)
John
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THANKS
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If I add a cm19a to my activehome pro
computer, will i be able to reach the ninja
pan and tilt mount more reliably with the
scanpad remote. Do I need to have Iwitness
installed to make this work. Thanks in
advance.
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The ninja pan and tilt commands are sent by
RF from the remote directly to the mount.
The signal that switches the addressable
power supplies goes to a tranceiver and then
sent over the powerline to the supplies. I
believe the pan and tilt commands are the
extended command type and are not processed
by the tranceivers at all. Same for the RF
Repeaters I don't think they repeat the
extended commands.
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Just checked the install sheet. The cm19a is
a tranceiver so if the software supports
sending the ninja control codes it can
support the pan and tilt functions.
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Yes, that is correct, the CM-19a both
listens and talks, BUT you are also correct,
in that the NINJA gets its motion commands
directly from the hand held remote. You
would have to add software (from where I
don't know) that responds to a received hand
held remote CM-19a motion command intended
for a NINJA and then retransmits, or
echos,it. I don't know if any X10 or
Activehome software does this. This also
means that the Ninja might get its signals
from both sources at times and do things
twice. That may be a problem that could be
lived with.
In short, I'll bet that that the answer to
your question about improving the strength
of the hand held remote commands with a
CM19a is a "NO".
John
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A quick, simple, and ugly antenna mod that was effective for me: aluminum foil. I was having sporadic issues communicating to modules on the other side of the house - some days it worked great, other times almost not at all. I took a small section of aluminum foil and rolled it into about a 12" rod. I threaded the CM19A antenna into one end and secured the other end to the wall with tape, with the new foil "antenna" oriented vertically. It looks ugly as sin, but i saw an immediate improvement in signal strength, and it solved my problems. Worth a shot if you're like me and too lazy to try the other suggested mods.
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The Ninja protocol is detailed at http://davehouston.org/cr14a-rf.htm (http://davehouston.org/cr14a-rf.htm). The pan & tilt commands are sent directly via RF, not by the powerline.
While it might be a bit awkward to add to a handheld remote almost anything will improve the range of most X-10 hand-held remotes. I've shown how to vastly improve the range of their wireless switches here http://davehouston.org/passive.htm (http://davehouston.org/passive.htm).
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The antenna length for 312 MHz at 1/2 wavelength is 18 inches and 9 inches for 1/4 wavelength. I am not sure how long the antenna is initially, but I would guess about 9 inches. So extending it another 9 inches to 18 will probably make a difference.
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Schematic says 240mm. ~9.45" That sounds about right for the X10 310 MHz.
In mine about half of the wire is in the small external tube antenna and the other half is glued around the inside of the case.
My early 2004 units. The inside portion of the wire is in a random ball of confusion and not neat at all.
Just measured one of my CM15A antenna tubes. Close to 4 3/4" ???
So part of the 9.45" is wrapped around the inside of the CM15As case.
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1. Add a coax jack to the CM19a:
http://marc.merlins.org/perso/linux/post_2011-07-24_Hacking-an-external-antenna-onto-an-X10-CM19a_-and-adding-misterhouse-support.html
2. Use a better antenna:
http://www.radioshack.com/product/index.jsp?productId=2103641#
3. Use 50ohm coax, not 75ohm cable tv coax
4. WRAP THE CM19A in aluminum foil. I used to do this to my W800, and it really seems to help.